Quantification of the expression level of integrin receptor αvβ3 in cell lines and MR imaging with antibody-coated iron oxide particles
✍ Scribed by Sabrina Benedetto; Roberta Pulito; Simonetta Geninatti Crich; Guido Tarone; Silvio Aime; Lorenzo Silengo; Jörg Hamm
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 378 KB
- Volume
- 56
- Category
- Article
- ISSN
- 0740-3194
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✦ Synopsis
Abstract
Targeted imaging requires site‐specific accumulation of a contrast agent (CA), and the properties of that agent must be selected according to the abundance of the target to obtain a signal above the detection limit of the instrument. However, numerical estimates of receptors per cell are rarely found in the literature. Integrin receptors would be particularly promising targets because of their accessibility from the blood stream and expression on activated neovascular endothelial cells. We systematically estimated the number of integrin receptors of cell lines and primary cells by flow cytometry analysis. Since integrin receptors are heterodimeric molecules, and α~v~ forms complexes with various β subunits, the numbers of α~v~ and β~3~ subunits are therefore dissimilar. The observed values are 3 · 10^3^–1.4 · 10^4^/cell for α~v~, and 5.3 · 10^2^–1.1 · 10^4^/cell for β~3~. Despite the low number of exposed receptors, we show that up to single‐cell MR visualization can be achieved with the use of iron oxide beads complexed with antibodies as CAs. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.